While tris are the most 'stable' shapes, quads will make your OBJ smaller and work fine provided the digits are high enough. Of course, the figits being higher will also make your mesh bigger (more bits per vertex), but the object will still have a lower poly count and render faster at least (because once Poser has it in memory it's using a short or long float, as necessary, to store it in memory, and this your hardware is the limit on resolution, and the bits used to store the number get much less)